As this type of weighing apparatus, for example, an electromagnetic balance type electronic balance has been provided. In the electromagnetic balance type weighing apparatus, when a weighing object is placed on a weighing pan, its load is transmitted to a beam being a load transmission mechanism, and the beam turns about a fulcrum, and the side connecting with an electromagnetic unit is also displaced due to the force. The displacement is sensed by an output voltage from a displacement detection sensor, current flows to a coil of the electromagnetic unit so as to cancel such displacement and balance said beam, and mass is measured by measuring the quantity of the electricity (Patent Literature 1).
Mass sensors to be used for weighing apparatuses include load cell types that use displacement of strain gauges and electrostatic capacitance types that measure displacement based on electrostatic capacitance of the sensors and weighing objects, besides the electromagnetic balance types described above, and all mass sensors are the same in the point of receiving mass×acceleration of gravity as a load, and measures mass from an electrical signal corresponding to displacement of an internal structure of the apparatus at that time.
Such weighing apparatuses have been recently introduced into production lines to perform weighing automatically such as production facilities, and particularly, on a production line called an automated machine, a weighing object is automatically placed on the weighing apparatus and mechanically measured by use of a production fixture using an actuator such as a motor or air cylinder.